1. Field of the Invention
The present invention relates generally to a relatively thin and slender metal pipe having a diameter of about 20 mm or less and arranged as feed passages for feeding oil and air to automobiles and various machines and apparatus and, more particularly, to a connection structure and process for connecting an eye-joint acting as a connecting fitting at a connecting end portion.
2. Description of the Prior Art
A branch pipe (21'), which has a fitting hole (23) leading to an annular groove (22) formed in the head of an eye-joint body (21), and a metal pipe (P.sub.1) are connected to each other by welding them at (W), such that a connection end portion (P.sub.1 ') of the metal pipe (P.sub.1) is inserted in the fitting hole (23) of the branch pipe (21').
In this prior art, however, the welding work (W) has not only invited a reduction in the workability but also often caused a leakage because of the uncertain work. At the same time, the overheating by the torch for the welding operation has raised a problem that a cracking or breakage is caused with the arrangement in a vibrating state at the side of the metal pipe (P.sub.1) in the vicinity of the connection end portion. In relation to the welding work (W), on the other hand, it has been impossible to use the eye-joint body (21) and the metal pipe (P.sub.1) which are either plated with a corrosion-resistant material or coated with a resin in advance, and this plating or coating treatment is required after the welding operation. As a result, the metal pipe (P.sub.1), which has already been bent into a complicated shape, may be poorly plated or coated to an uneven thickness in the plated or coated film.